1. Field of the Inventions
The present inventions relate generally to apparatus and methods for inserting an ocular implant into an eye.
2. Description of the Related Art
There are a variety of instances where an ocular implant is inserted into the anterior chamber, posterior chamber, cornea, vitreous space and/or other portion of an eye. Exemplary ocular implants include, but are not limited to, lenses, capsular tension rings, ocular prosthesis and lamellar transplants. An intraocular lens (IOL), for example, may be inserted into an aphakic eye that has undergone a cataract surgery or may be inserted into a phakic eye during a refractive surgery. One type of lens is a foldable lens. Foldable lenses are formed from soft material such as a silicone elastomer, soft acrylic, or hydrogel and may be inserted into the eye through a small incision. Lens insertion apparatus, which may be used to push a foldable lens into an eye through a nozzle, generally include screw-type insertion apparatus and push-type insertion apparatus. In both cases, the lens insertion apparatus may include a plunger that is used to push a folded lens through the nozzle into the eye by way of an incision that is relatively small, e.g., an incision that is smaller than the diameter of an IOL optic.
Loading an ocular implant into an inserter can be a troublesome portion of the insertion procedure. The implant may be contaminated, damaged or improperly placed into the inserter by operator, e.g., a surgeon or assistant. Accordingly, in some instances, the insertion apparatus is preloaded, i.e., the insertion apparatus is shipped from the factory with the ocular implant (e.g., an IOL) stored therein. An operator using a preloaded inserter does not place the implant into the insertion apparatus, thereby eliminating the possibility of the aforementioned operator error associated with loading.
In addition to the basic functions of storing and inserting an IOL or other ocular implant, it may also be desirable for the insertion apparatus to minimize the physical load on the ocular implant during storage in order to ensure that the ocular implant returns to its unstressed state after being inserted into the eye. It may also be desirable to fold the IOL or other ocular implant into as small a state as possible in order to reduce the size of the incision and the likelihood of corneal astigmatism caused by the surgery or infection. Thus, the desired insertion apparatus must be able to fold the unstressed ocular implant into a small state in a predetermined direction, and into a predetermined shape, in order to insure that the plunger can move the folded ocular implant through the nozzle without the insertion apparatus becoming clogged at or near the nozzle or the ocular implant being damaged. To that end, instead of using only a plunger to move the lens through the folding and insertion processes, some insertion apparatus have been configured to fold and move an IOL in stepwise fashion through the use of multiple IOL moving structures. Examples of such insertion apparatus are illustrated and described in PCT Pub. No. WO 2009/148091 (also published as US 2011/0082463) and Laid-open JP Pat. Pub. No. 2001-104347 (also published as US 2001/0007942).
The present inventor has, however, determined that insertion apparatus with multiple ocular implant moving structures are susceptible to improvement. For example, the present inventor has determined that such insertion apparatus are susceptible to erroneous operation, such as use of the moving structures in an incorrect sequence.